Annette Horstmann

• Dr. rer. nat.
• Professor at University of Helsinki

Objective: In this study, we investigate the brain mechanisms of the conscious regulation of the desire for food using functional magnetic resonance imaging. Further, we examine associations between hemodynamic responses and participants' cognitive restraint of eating (CRE), as well as their susceptibility to uncontrolled eating. Subjects: Seven...

Alterations in the dopaminergic system have been implicated in both animal and human obesity. However, to date, a comprehensive model on the nature and functional relevance of this relationship is missing. In particular, human data remain equivocal in that seemingly inconsistent reports exist of positive, negative or even no relationships between d...

Over the past years, evidence has accumulated that obesity is intimately linked to the integrity of the fronto-striatal system of the human brain. However, the nature and causality of this relationship remains elusive. The fronto-striatal system is responsible for higher order cognitive functions such as learning, working memory, decision-making an...

Prediction errors (PEs) encode the difference between expected and actual action outcomes in the brain via dopaminergic modulation. Integration of these learning signals ensures efficient behavioral adaptation. Obesity has recently been linked to altered dopaminergic fronto-striatal circuits, thus implying impairments in cognitive domains that rely...

Obesity is associated with alterations in dopaminergic transmission and cognitive function. Recent findings from rodent studies suggest that diets rich in saturated fat and refined sugars (HFS) induce changes in the dopamine system independent of excessive body weight. However, so far the impact of HFS on the human brain has not been investigated....

Consumption of ultra-processed foods (UPFs) increases overall caloric intake and is associated with obesity, cardiovascular disease, and brain pathology. There is scant evidence as to why UPF consumption leads to increased caloric intake and whether the negative health consequences are due to adiposity or characteristics of UPFs. Using the UK Bioba...

In the complex landscape of daily life, we continuously balance between maintaining focus despite distractions and flexibly updating focus when needed—a cognitive process governed by a mechanism known as working memory gating. While much research has focused on the neural locus of this mechanism, less is known about the underlying neural dynamics....

Learning and decision-making undergo substantial developmental changes, with adolescence being a particular vulnerable window of opportunity. In adolescents, developmental changes in specific choice behaviors have been observed (e.g., goal-directed behavior, motivational influences over choice). Elevated levels of decision noise, i.e., choosing sub...

Everyday life requires an adaptive balance between distraction-resistant maintenance of information and the flexibility to update this information when needed. These opposing mechanisms are proposed to be balanced through a working memory gating mechanism. Prior research indicates that obesity may elevate the risk of working memory deficits, yet th...

Everyday life requires an adaptive balance between distraction-resistant maintenance of information and the flexibility to update this information when needed. These opposing mechanisms are proposed to be balanced through a working memory gating mechanism. Prior research indicates that obesity may elevate the risk of working memory deficits, yet th...

Background: Modern food items often contain high proportions of saturated fats and refined carbohydrates. Such dietary compositions contribute to the prevalence of obesity and metabolic disease. Food images are a valuable tool to study these diet effects on eating behavior and obesity development. Aims: Creating and validating a novel food picture...

Everyday life requires an adaptive balance between distraction-resistant maintenance of information and the flexibility to update this information when needed. These opposing mechanisms are proposed to be balanced through a working memory gating mechanism. Prior research indicates that obesity may elevate the risk of working memory deficits, yet th...

Everyday life requires an adaptive balance between distraction-resistant maintenance of information and the flexibility to update this information when needed. These opposing mechanisms are proposed to be balanced through a working memory gating mechanism. Prior research indicates that obesity may elevate the risk of working memory deficits, yet th...

Everyday life requires an adaptive balance between distraction-resistant maintenance of information and the flexibility to update this information when needed. These opposing mechanisms are proposed to be balanced through a working memory gating mechanism. Prior research indicates that obesity may elevate the risk of working memory deficits, yet th...

Background – Binge Eating Disorder (BED) is thought of as a disorder of cognitive control but evidence regarding its neurocognitive mechanisms is inconclusive. Key limitations in prior research are a lack of consistent separation between effects of BED and obesity, and a disregard for self-report evidence suggesting that neurocognitive alterations...

Computational models and neurophysiological data propose that a ‘gating mechanism’ coordinates distractor-resistant maintenance and flexible updating of working memory contents: While maintenance of information is mainly implemented in the prefrontal cortex, updating of information is signaled by phasic increases in dopamine in the striatum. Previo...

Background: Bariatric surgery has been widely recognized as the most efficient long-term treatment method in severe obesity, yet therapy success shows considerable interindividual variability. Postoperative metabolic adaptations, including improved gut hormone secretion (GLP-1, PYY and ghrelin), and restored executive function may play an explanat...

Objective This study aimed to evaluate the effectiveness of the app‐based, multimodal weight loss program zanadio. Methods A randomized‐controlled trial was conducted from January 2021 to March 2022. A total of 150 adults with obesity were randomized into an intervention group and used zanadio for 1 year or into a wait list control group. The prim...

Precisely charting the maturation of core neurocognitive functions such as reinforcement learning (RL) and flexible adaptation to changing action-outcome contingencies is key for developmental neuroscience and adjacent fields like developmental psychiatry. However, research in this area is both sparse and conflicted, especially regarding potentiall...

Cognition and brain structure undergo significant maturation from adolescence into adulthood. Model-based (MB) control is known to increase across development, which is mediated by cognitive abilities. Here, we asked two questions unaddressed in previous developmental studies: Firstly, what are the brain structural correlates of age-related increas...

Animal studies indicate that a high-fat/high-sugar diet (HFS) can change dopamine signal transmission in the brain, which could promote maladaptive behavior and decision-making. Such diet-induced changes may also explain observed alterations in the dopamine system in human obesity. Genetic variants that modulate dopamine transmission have been prop...

Background While necessary for studying dietary decision-making or public health, estimates of nutrient supply based on self-reported food intake are barely accessible or fully lacking and remain a challenge in human research. In particular, detailed information on dietary fiber is limited. In this study we introduce an automated openly available a...

Background Bariatric surgery has been widely recognized as the most efficient long-term treatment method in severe obesity, yet therapy success shows considerable interindividual variability. Postoperative metabolic adaptations, including improved gut hormone secretion (GLP-1, PYY and ghrelin), and restored executive function may play an explanator...

Adolescents undergo maturation in cognition and brain structure. Model-based (MB) control is known to increase from childhood to young adulthood, which is mediated by cognitive abilities. Here, we asked two questions unaddressed in previous developmental studies: Firstly, what are the brain structural correlates of age-related increases in MB contr...

Precisely charting the maturation of core neurocognitive functions such as reinforcement learning (RL) and flexible adaptation to changing action-outcome contingencies is key for developmental neuroscience. It can also help us understand how disruptions during development might contribute to the onset of psychopathology. However, research in this a...

Amygdala dysregulation is a core dysfunction in multiple psychiatric disorders. Thus, the introduction of Amygdala self-modulation through NeuroFeedback (NF) is a valuable non-invasive intervention tool. Yet, the feasibility and best practices of Amygdala-NF have not been systematically examined. The current perspective presents a thorough review o...

Background: Roux-en-Y gastric bypass (RYGB) surgery belongs to the most frequently performed surgical therapeutic strategies against adiposity and its comorbidities. However, outcome is limited in a substantial cohort of patients with inadequate primary weight loss or considerable weight regain. In this study, gut microbiota composition and systemi...

Dopamine is a neurotransmitter that plays a crucial role in adaptive behavior. A wealth of studies suggests obesity-related alterations in the central dopamine system. The most direct evidence for such differences in humans comes from molecular neuroimaging studies using positron emission tomography (PET) and single-photon emission computed tomogra...

Background: While necessary for studying dietary decision-making or public health, estimates of nutrient supply based on self-reported food intake are barely accessible or fully lacking and remain a challenge in human research. In particular, detailed information on dietary fiber is limited. In this study we introduce an automated openly available...

Background: While necessary for studying dietary decision-making or public health, estimates of nutrient supply based on self-reported food intake are barely accessible or fully lacking and remain a challenge in human research. In particular, detailed information on dietary fiber is limited. In this study we introduce an automated openly available...

Amygdala dysregulation is core to multiple psychiatric disorders. Real-time fMRI enables Amygdala self-modulation through NeuroFeedback (NF). Despite a surge in Amygdala-NF studies, a systematic quantification of self-modulation is lacking. Amygdala-NF dissemination is further restricted by absence of unifying framework dictating design choices and...

The gut microbiome has been speculated to modulate feeding behavior through multiple factors, including short-chain fatty acids (SCFA). Evidence on this relationship in humans is however lacking. We aimed to explore if specific bacterial genera relate to eating behavior, diet, and SCFA in adults. Moreover, we tested whether eating-related microbiot...

Smell perception plays a role in eating behavior and might be involved in the development of obesity. In fact, olfactory function is impaired in obesity and might depend on metabolic health factors. To date, the underlying neural mechanisms remain unclear. Here, we investigate neural processing of food-related odors in normal-weight, overweight and...

Die vorläufigen Daten zeigen, dass die Nutzung von zanadio bereits nach 3 Monaten zu einer signifikanten Gewichtsreduktion führt. Somit kann zanadio als kostengünstiges und ortsunabhängiges Behandlungsprogramm positiv zur Versorgungssituation der erwachsenen adipösen Bevölkerung beitragen. Die abschließende Evaluation des digitalen Therapiekonzepts...

Recurring episodes of excessive food intake in binge eating disorder can be understood through the lens of behavioral control systems: patients repeat maladaptive behaviors against their explicit intent. Self-report measures show enhanced impulsivity and compulsivity in binge eating (BE) but are agnostic as to the processes that might lead to impul...

Objective Food odors serve as powerful stimuli signaling the food quality and energy density and direct food‐specific appetite and consumption. This study explored obesity‐related brain activation in response to odors related to high‐ or low‐energy‐dense foods. Methods Seventeen participants with obesity (BMI > 30 kg/m²; 4 males and 13 females) an...

Objectives: The gut microbiome modulates human brain function and eating behavior through multiple factors, including short-chain fatty acid (SCFA) signaling. We investigated which bacterial genera relate to eating behavior, diet and SCFA metabolites in overweight adults. In addition, we tested whether eating-related microbiota predict treatment su...

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Recurring episodes of excessive food intake in binge eating disorder can be understood through the lens of behavioral control systems: patients repeat maladaptive behaviors against their explicit intent. Self-report measures show enhanced impulsivity and compulsivity in binge eating (BE). Task-based neurocognitive investigations can tap into proces...

Consuming more energy than is expended may reflect a failure of control over eating behaviour in obesity. Behavioural control arises from a balance between two dissociable strategies of reinforcement learning: model-free and model-based. We hypothesized that weight status relates to an imbalance in reliance on model-based and model-free control, an...

Computational modeling of dopamine transmission is challenged by complex underlying mechanisms. Here we present a new computational model that (I) simultaneously regards release, diffusion and uptake of dopamine, (II) considers multiple terminal release events and (III) comprises both synaptic and volume transmission by incorporating the geometry o...

Smell perception plays an important role in eating behavior and might be involved in body weight gain. Since a body of literature implies that olfactory perception and function is hampered in obesity, we here investigate neuroanatomical correlates of this phenomenon. We assessed olfactory bulb (OB) volume with magnetic resonance imaging in 67 healt...

Obesity is associated with alterations in dopaminergic transmission and cognitive function. Rodent studies suggest that diets rich in saturated fat and refined sugars (HFS), as opposed to diets diets low in saturated fat and refined sugars (LFS), change the dopamine system independent of excessive body weight. However, the impact of HFS on the huma...

People with olfactory loss may choose foods rich in sugar, salt and fat to compensate their loss—foods that constitute a Western-style diet (WSD). However, olfactory dysfunction has not been consistently linked to any particular type of dietary change. Here we considered whether the aetiology of olfactory dysfunction may affect consumption of a WSD...

The worldwide obesity epidemic is a major health problem driven by the modern food environment. Recently, it has been shown that smell perception plays a key role in eating behavior and is altered in obesity. However, the underlying mechanisms of this phenomenon are not well understood yet. Since the olfactory system is closely linked to the endocr...

Temporal impulsivity, the tendency to choose a smaller, sooner over a larger, delayed reward, is associated with single nucleotide polymorphisms (SNPs) in COMT and DRD2-related ANKK1 genes, whose products regulate dopaminergic transmission in the brain. Temporal impulsivity is also consistently associated with obesity, sometimes in a gender-depende...

It is a widely held view that humans have control over their food choices and consumption. However, research also suggests that eating behavior is often triggered by contextual cues and guided by automaticities and habits. Interestingly, the dichotomy between automatic and controlled processing has recently been challenged, suggesting that they may...

Introduction: Assessment of olfactory performance is of high clinical interest in the contexts of smell loss as well as neurological diseases, and recently gained attention in obesity research. Available olfactory tests, especially for assessing olfactory sensitivity, are time-consuming and require high cognitive capacity. Therefore, we aimed to es...

Objective Binge eating is characterized by episodes of uncontrolled eating, within discrete periods of time. Although it is usually described in obese individuals or as a symptom of Binge Eating Disorder (BED), this behavior can also occur in the normal‐weight (NW) population. An interesting premise suggests that impulsivity might contribute to the...

The original article unfortunately contained a mistake. In the online version of the paper, the entire Box 1 is missing, and the labels of the 2 tables are swapped. The original version has been corrected.

Much of our behaviour is driven by two motivational dimensions—approach and avoidance. These have been related to frontal hemispheric asymmetries in clinical and resting‐state EEG studies: Approach was linked to higher activity of the left relative to the right hemisphere, while avoidance was related to the opposite pattern. Increased approach beha...

Emotions can influence our eating behaviors. Facing an acute stressor or being in a positive mood are examples of situations that tend to modify appetite. However, the question of how the brain integrates these emotion-related changes in food processing remains elusive. Here, we designed an emotional priming fMRI task to test if amygdala activity d...

Background: The Dietary Fat and Free Sugar-Short Questionnaire (DFS) is a cost- and time-efficient self-report screening instrument to estimate dietary intake of saturated fat and free sugar. To date, only the English version has been psychometrically evaluated. We assessed the psychometric characteristics of the German version of the DFS in indiv...

Purpose of Review Animal and human studies suggest that diet-induced obesity and plasticity in the central dopaminergic system are linked. However, it is unclear whether observed changes depend on diet or obesity, and whether they are specific to brain regions and cognitive functions. Here, we focus on neural and cognitive changes in frontostriatal...

The operation span task is a well-validated measure of the executive component of working memory. Previous scoring systems of this task focus predominantly on the span part of the task, while the distractor – math task – serves as an exclusion criterion for test assessment only. Here, we propose a new Math-Item-Sequence (MIS) system to score perfor...

Previous research has shown that emotions can influence our eating behaviors. Facing an acute stressor or being in a positive mood state are examples of situations that tend to modify appetite. However, the question of how the brain integrates food processing and emotional processing remains largely elusive. Here we designed an emotional priming fM...

Consuming more energy than is expended may reflect a failure of control over eating behaviour in obesity. Behavioural control arises from a balance between two dissociable strategies of reinforcement learning: model-free and model-based. We hypothesized that weight status relates to an imbalance in reliance on model-based and model-free control, an...

Much of our behaviour is driven by two motivational dimensions - approach and avoidance. These have been related to frontal hemispheric asymmetries in clinical and resting-state EEG studies: approach was linked to higher activity of the left relative to the right hemisphere, while avoidance was related to the opposite pattern. Increased approach be...

Altered eating behavior due to modern, food-enriched environments has a share in the recent obesity upsurge, though the exact mechanisms remain unclear. This study aims to assess whether higher weight or weight gain are related to stronger effects of external cues on motivation-driven behavior. 51 people with and without obesity completed an appeti...

Converging evidence suggests that dysfunctional inhibitory control might be at the roots of overeating and binge eating disorder (BED). The majority of these results stems from studies on obese populations, however we hypothesized that potential prodromes might be evident also in non-clinical conditions, when binge eating episodes are present (with...

Background: In brain, CREB-regulated transcription co-activator 1 (CRTC1) is involved in metabolic dysregulation. In humans a SNP in CRTC1 was associated to body fat percentage and two SNPs affected RNA Pol II binding and chromatin structure, implying epigenetic regulation of CRTC1. We sought to understand the relevance of CRTC1 SNPs, DNA methylat...

Obesity is associated with automatically approaching problematic stimuli, such as unhealthy food. Cognitive bias modification (CBM) could beneficially impact problematic approach behavior. However, it is unclear which mechanisms are targeted by CBM in obesity. Candidate mechanisms include: (1) altering reward value of food stimuli; and (2) strength...

Background: The Dietary Fat and free Sugar – Short Questionnaire (DFS) is a cost- and time-efficient self-report screening instrument to estimate dietary intake of saturated fat and free sugar. To date, only the English version has been psychometrically evaluated. We assessed the psychometric characteristics of the German version of the DFS in norm...

We present a publicly available dataset of 228 healthy participants comprising a young (N=154, 25.1±3.1 years, range 20–35 years, 45 female) and an elderly group (N=74, 67.6±4.7 years, range 59–77 years, 37 female) acquired cross-sectionally in Leipzig, Germany, between 2013 and 2015 to study mind-body-emotion interactions. During a two-day assessm...

We present a publicly available dataset of 227 healthy participants comprising a young (N=153, 25.1±3.1 years, range 20–35 years, 45 female) and an elderly group (N=74, 67.6±4.7 years, range 59–77 years, 37 female) acquired cross-sectionally in Leipzig, Germany, between 2013 and 2015 to study mind-body-emotion interactions. During a two-day assessm...

Entscheidungen zu fällen, ist ein integraler Bestandteil des täglichen Lebens. Im Kontext von Adipositas sind Entscheidungen von besonderem Interesse, die das Essverhalten und die physische Aktivität beeinflussen. Wie wir uns letztendlich entscheiden, hängt von einer Fülle von Faktoren ab. Diese sind unter anderem der erwartete Belohnungswert, der...

Obese individuals discount future rewards to a higher degree than lean individuals, which is generally considered disadvantageous. Moreover, their decisions are altered more easily by decision-irrelevant cues. Here, we investigated neural correlates of this phenomenon using functional MRI. We tested 30 lean and 26 obese human subjects on a primed d...

Objective: Obesity is associated with automatically approaching problematic stimuli, such as unhealthy food. Cognitive bias modification (CBM) could beneficially impact on problematic approach behavior. However, it is unclear which mechanisms are targeted by CBM in obesity: Candidate mechanisms include (1) altering reward value of food stimuli or (...

Individuals with obesity are often characterized by alterations in reward processing. This may affect how new information is used to update stimulus values during reinforcement-based learning. Here, we investigated obesity-related changes in non-food reinforcement processing, their impact on learning performance as well as the neural underpinnings...

Goal-directed behaviour depends on successful association of environmental cues with reward or punishment. Obesity has been linked to diminished learning success in this domain. In contrast, here we demonstrate superior learning in obese participants independent of reward type. We tested association learning in 85 participants with a wide body-mass...

Eating behavior in obesity resembles addictive disorders in that individuals have difficulties inhibiting problematic eating behavior. They show an approach bias - a tendency to approach rather than avoid problematic stimuli. Here, we investigate the existence of such a bias towards healthy and unhealthy food in individuals with normal-weight and o...

Real-time fMRI neurofeedback is a feasible tool to learn the volitional regulation of brain activity. So far, most studies provide continuous feedback information that is presented upon every volume acquisition. Although this maximizes the temporal resolution of feedback information, it may be accompanied by some disadvantages. Participants can be...

Background: The central nervous effects of gastrointestinal and adipocyte derived hormones strongly modulate eating behavior. However, little is known about their effects on brain activity in humans. Here, we investigated the effects of exenatide, a GLP-1 analogue, in healthy volunteers, and leptin substitution in leptin-deficient patients on brain...

Objective The current study investigates potential pathways from socio-economic status (SES) to BMI in the adult population, considering psychological domains of eating behaviour (restrained eating, uncontrolled eating, emotional eating) as potential mediators stratified for sex. Design Data were derived from the population-based cross-sectional L...

Individuals with obesity in Western societies often face weight-related stigmatization and social exclusion. Recurrent exposure to prejudice and negative social feedback alters one’s behavior in future social interactions. In this study, we aimed to investigate autonomic nervous system and affective responses to social interactions in individuals w...

Instrumental learning and decision-making rely on two parallel systems: a goal-directed and a habitual system. In the past decade, several paradigms have been developed to study these systems in animals and humans by means of e.g. overtraining, devaluation procedures and sequential decision-making. These different paradigms are thought to measure t...

Impaired self-regulation, especially in food-specific situations, has been linked to childhood obesity. These deficits may be acquired during the development of obesity rather than being a prerequisite thereof. The current study hence focused on an at risk population vs. controls: Normal-weight children of obese and normal-weight parents were teste...

According to dual-system theory, instrumental learning and performance depend on the balance between goal-directed and habitual action control. Overreliance on habits has been argued to characterize clinical conditions such as drug addiction or obsessive-compulsive disorder as well as obesity and excessive impulsivity. A tendency towards habitual a...

Incidental learning of appropriate stimulus-response associations is crucial for optimal functioning within our complex environment. Positive and negative prediction errors (PEs) serve as neural teaching signals within distinct (‘direct’/‘indirect’) dopaminergic pathways to update associations and optimize subsequent behavior. Using a computational...

Recent research indicates that reduced inhibitory control is associated with higher body mass index (BMI), higher food craving and increased food intake. However, experimental evidence for the relationship between response inhibition and weight status is inconsistent and to date has been investigated predominantly in women. In the current study, 56...